Biological-ecological synergistic purification system for road pollutants in municipal roads

Abstract

This invention relates to a biological-ecological synergistic purification system for road runoff pollutants in municipal roads, belonging to the field of municipal road rainwater treatment technology. With the acceleration of urbanization, the pollution of natural water bodies by road runoff pollutants is becoming increasingly serious. This biological-ecological synergistic purification system uses a bar screen to intercept large particles and sludge, a biofilm reactor to degrade pollutants using a combined packing layer, an ecological filter to further purify the water using multi-layered filter media and plants, and an ultraviolet disinfection device to kill pathogens. Finally, the purified water is discharged into natural water bodies. It is mainly used to effectively purify road runoff pollutants in municipal roads and protect the natural aquatic environment.

Description

Technical Field

[0001] This invention relates to the field of municipal road stormwater treatment technology. More specifically, this invention relates to a biological-ecological synergistic purification system for road runoff pollutants in municipal roads. Background Technology

[0002] With rapid urbanization, the scale of municipal road construction is constantly expanding. As one of the main sources of urban non-point source pollution, road runoff carries a large number of pollutants such as suspended solids, organic matter, and heavy metals, posing a serious threat to the urban water environment.

[0003] Traditional road flow treatment methods mainly focus on simple physical interception and sedimentation, such as installing simple screens or sedimentation tanks at rainwater collection inlets. While these methods can remove some large suspended particles, they are ineffective at removing dissolved organic matter, heavy metals, and microorganisms. This is because traditional methods rely solely on physical processes and lack mechanisms for deep treatment of pollutants.

[0004] The treatment process also presents challenges in sludge disposal. If the settled sludge is not treated promptly and effectively, it can lead to clogged screens and sedimentation tanks, affecting the normal operation of the treatment system. Furthermore, traditional sludge treatment methods are inefficient.

[0005] Furthermore, traditional treatment methods often lack effective disinfection measures for microbial contamination in road runoff. Direct discharge of road runoff containing large amounts of pathogens into natural water bodies poses potential harm to the aquatic ecosystem and human health. Therefore, developing an efficient and stable municipal road runoff pollutant purification system is of significant practical importance. Summary of the Invention

[0006] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0007] To achieve these objectives and other advantages according to the present invention, a biological-ecological synergistic purification system for municipal roadway pollutants is provided, comprising:

[0008] A bar screen interception device is located downstream of a road rainwater collection inlet. The bar screen interception device includes an inclined bar screen with a sedimentation tank at the bottom of the inclined bar screen. The bottom of the sedimentation tank is connected to a sludge discharge pipe, and the end of the sludge discharge pipe is connected to a sludge treatment device.

[0009] The biofilm reactor has its inlet connected to the outlet of the bar screen. The biofilm reactor contains a combined packing layer, which consists of, from bottom to top, a volcanic rock packing layer with a particle size of 10-15 mm, a ceramic granule packing layer with a particle size of 5-8 mm, and a polyurethane biological carrier layer with a specific surface area greater than 800 m² / m³. The total thickness of the combined packing layer is 1.2-1.5 m. An aeration system is installed at the bottom of the biofilm reactor, with an aeration output intensity of 0.8-1.2 m³ / (m²·h).

[0010] The ecological filter has its inlet connected to the outlet of the biofilm reactor. From bottom to top, the ecological filter is equipped with a gravel layer of 0.5-0.8m thickness, a zeolite layer of 0.3-0.5m thickness, and a humus planting layer of 0.2-0.3m thickness. The gravel layer has a particle size of 20-30mm, the zeolite layer has a particle size of 5-10mm, and the humus planting layer is planted with reeds, calamus, and irises. The bottom of the ecological filter is equipped with a perforated water collection pipe with an opening rate of 15%-20%.

[0011] The ultraviolet disinfection device is located at the outlet of the ecological filter pond, and the outlet of the ultraviolet disinfection device is connected to the natural water body discharge pipe.

[0012] Preferably, a transition buffer layer is provided between the volcanic rock packing layer and the ceramsite packing layer of the combined packing layer. The transition buffer layer is composed of zeolite particles with a particle size of 8-10 mm and a calcium ion exchange capacity of ≥200 mg / g, and has a thickness of 50-80 mm.

[0013] The polyurethane biocarrier layer has a through-hole microporous channel with a diameter of 1-1.5 mm. The inner wall of the microporous channel is coated with a nano-titanium dioxide photocatalytic coating with a thickness of 10-20 μm. The thickness of the polyurethane biocarrier layer is 0.4-0.6 μm, and the porosity of its microporous channel is ≥85%, and the wet compression resilience is ≥90%.

[0014] The aeration pipes of the aeration system form a swirling aeration structure at the bottom of the combined packing layer, and the aeration holes of the aeration system are tilted at an angle of 30-45 degrees.

[0015] Preferably, the humus planting layer comprises the following components blended in a specific mass ratio:

[0016] The soil contains 60%-70% humus, with an organic matter content ≥25% and a pH of 6.0-7.5.

[0017] 15%-20% modified biochar particles, particle size 2-4mm, specific surface area ≥500m² / g, surface loading of 3%-5% Fe-Mn oxide by mass fraction;

[0018] 10%-15% diatomite-zeolite composite particles, particle size 1-3mm, calcium ion exchange capacity ≥180mg / g;

[0019] 5%-8% slow-release microbial inoculant granules, including nitrifying bacteria, denitrifying bacteria, and plant rhizosphere growth-promoting bacteria, with a content ≥1×10 6 CFU / g, ≥5×10 5 CFU / g, ≥2×10 6 CFU / g;

[0020] The humus planting layer is divided into a top layer and a bottom layer from top to bottom. The top layer is 50-80mm thick and includes a mixture of humus and modified biochar in a 7:3 mass ratio. Reeds, calamus and irises are planted in the top layer, with the three plants arranged at a 2:1:1 ratio. Spiral drainage channels are provided in the root zone. The spiral drainage channels are 20-30mm deep and the channel spacing is 80-100mm.

[0021] The bottom layer is 150-220mm thick and consists of a mixture of humus and diatomaceous earth-zeolite composite particles in a 6:4 mass ratio. The bottom layer is pre-embedded with permeable ceramic granule pipes with a diameter of 10-15mm. The horizontal spacing of the permeable ceramic granule pipes is 200-250mm and the vertical spacing is 100-150mm.

[0022] Preferably, the perforated water collection pipe is surrounded by a volcanic rock particle filter layer with a particle size of 3-5 mm, the thickness of the volcanic rock particle filter layer is 80-100 mm, and the porosity of the volcanic rock particles is 45%-55%.

[0023] The perforated water collection pipe is divided into upper and lower layers. The upper layer perforated water collection pipe has an opening direction of 15%-18% and an opening rate of 15%-18%. The lower layer perforated water collection pipe has an opening direction of 12%-15% and an opening rate of 12%-15%. The distance between the upper and lower layers of perforated water collection pipes is 200-250mm.

[0024] Preferably, it also includes a backwashing system, which includes a municipal water supply pipe and an ultraviolet disinfection return water pipe connected by a three-way valve. The backwash water is injected in reverse into the perforated water collection pipe through the backwashing branch pipe. The end of the backwashing branch pipe is connected to a sludge collection tank. The bottom of the sludge collection tank is connected to sludge treatment equipment through a screw conveyor.

[0025] The perforated water collection pipe is connected to a backwash branch pipe at its end. A pressure sensor is installed on the backwash branch pipe. When the pressure difference between the inside and outside of the water collection pipe exceeds the set threshold, the backwash mode is triggered.

[0026] Preferably, the inlet of the ultraviolet disinfection device is equipped with a turbidity sensor and a flow meter. When the turbidity is greater than 5 NTU or the flow rate exceeds the design value by 20%, the PLC controller will synchronously control the lamp power of the ultraviolet disinfection device to increase to 100%-110% and operate at overpower for no more than 30 minutes at a time.

[0027] An ultraviolet intensity monitoring probe is installed at the end of the ultraviolet disinfection device. When the detected dose is <30mJ / cm², the water flow residence time is extended to 1.2-1.5 times the original value.

[0028] Preferably, the sidewall of the sedimentation tank is equipped with an ultrasonic level sensor, the probe of which is 2 / 3 to 3 / 4 of the depth of the sedimentation tank, and the sensor is used to detect at a set frequency.

[0029] The sludge discharge pipe inlet is equipped with a pneumatic knife gate valve with a gate thickness of 8-10mm;

[0030] The ultrasonic level sensor is connected to the PLC controller. When the sludge layer height is detected to be greater than 1 / 2 of the sedimentation tank depth for three consecutive times, the PLC controller controls the pneumatic knife gate valve to fully open within 15 seconds to discharge sludge until the ultrasonic level sensor detects that the sludge layer height is less than the set low threshold. At this point, the pneumatic knife gate valve closes, the sludge discharge pipe outlet is connected to the screw conveyor inlet, and the screw conveyor outlet is connected to the sludge treatment equipment receiving bin.

[0031] Preferably, three dissolved oxygen sensors are spaced apart along the water flow direction in the biofilm reaction tank, located 200 mm above the bottom of the combined packing layer, 150 mm below the middle and top of the packing layer, respectively.

[0032] The blower of the aeration system is equipped with a frequency converter with an output frequency of 30-50Hz. The frequency converter is connected to the PLC controller via a 4-20mA signal.

[0033] The PLC controller has a built-in segmented control algorithm. When the dissolved oxygen sensor values ​​of any two sensors are <2.5mg / L, the blower frequency is increased to 40-45Hz. When the dissolved oxygen sensor values ​​of all three sensors are >3.0mg / L, the frequency is reduced to 35-38Hz.

[0034] The blower outlet pipe is equipped with a bypass pressure relief branch pipe with a solenoid valve. When the aeration intensity is >1.2m³ / (m²·h) for 5 minutes, the solenoid valve opens to 10%-15% of its opening.

[0035] The present invention has at least the following beneficial effects:

[0036] First, the invention achieves graded and synergistic removal of pollutants. It integrates physical interception, biodegradation, and plant absorption functions to form a step-by-step purification chain targeting pollutants of different particle sizes and properties. The grid intercepts large particulate impurities, the biofilm reactor decomposes dissolved organic matter, and the ecological filter removes nutrients through plant roots and packing material adsorption, thus achieving multi-dimensional pollution control.

[0037] Secondly, the biological and ecological functions complement each other. The highly efficient biofilm carrier of the combined packing layer and the root metabolism of wetland plants create a complementary effect. The microbial community is stably enriched on the surface of the packing material, and plant root exudates promote microbial activity, while absorbing and transforming pollutants, thus constructing a self-sustaining purification ecosystem.

[0038] Third, dynamic operational stability is improved. The optimized hydraulic conditions of the swirl aeration and guide channel structure enhance the system's adaptability to flow fluctuations. The intelligent control system automatically adjusts the aeration intensity and disinfection dosage based on water quality parameters, ensuring treatment efficiency during heavy rains and high pollution loads.

[0039] Fourth, it features long-term, low-maintenance operation. The modular packing layer design reduces the risk of clogging, and the backwashing mechanism and automatic sludge discharge function reduce the need for manual maintenance. The volcanic rock filter layer and ceramsite permeable pipe structure maintain long-term permeability and extend the service life of the filter.

[0040] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the processing equipment of the system according to one of the technical solutions of the present invention.

[0042] Explanation of reference numerals in the accompanying drawings: 100, bar screen interception device, 200, biofilm reaction tank, 300, ultraviolet disinfection device, 400, bar screen, 11, sedimentation tank, 12, sludge discharge pipe, 21, volcanic rock packing layer, 22, ceramsite packing layer, 23, polyurethane biological carrier layer, 24, transition buffer layer, 25, aeration pipe, 31, gravel layer, 32, humus planting layer, 33, perforated water collection pipe, 34, sludge collection tank. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0044] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the orientation or positional relationship indicated by the terms is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0045] like Figure 1As shown, this invention provides a biological-ecological synergistic purification system for roadside pollutants in municipal roads, comprising:

[0046] A bar screen interception device 100 is located downstream of a road rainwater collection inlet. The bar screen interception device 100 includes an inclined bar screen 11, a sedimentation tank 12 at the bottom of the inclined bar screen 11, a sludge discharge pipe 13 at the bottom of the sedimentation tank 12, and a sludge treatment device at the end of the sludge discharge pipe 13.

[0047] The biofilm reactor 200 has its inlet connected to the outlet of the bar screen 100. The biofilm reactor 200 is equipped with a combined packing layer, which consists of, from bottom to top, a volcanic rock packing layer 21 with a particle size of 10-15 mm, a ceramic granule packing layer 22 with a particle size of 5-8 mm, and a polyurethane biological carrier layer 23 with a specific surface area greater than 800 m² / m³. The total thickness of the combined packing layer is 1.2-1.5 m. The bottom of the biofilm reactor 200 is equipped with an aeration system with an output intensity of 0.8-1.2 m³ / (m²·h).

[0048] The ecological filter 300 has its inlet connected to the outlet of the biofilm reaction tank 200. The ecological filter 300 has a gravel layer 31 with a thickness of 0.5-0.8m, a zeolite layer 32 with a thickness of 0.3-0.5m, and a humus planting layer 33 with a thickness of 0.2-0.3m from bottom to top. The gravel layer 31 has a particle size of 20-30mm, the zeolite layer 32 has a particle size of 5-10mm, and the humus planting layer 33 is planted with reeds, calamus and irises. The bottom of the ecological filter 300 is equipped with a perforated water collection pipe 34 with an opening rate of 15%-20%.

[0049] The ultraviolet disinfection device 400 is located at the outlet of the ecological filter 300, and the outlet of the ultraviolet disinfection device 400 is connected to the natural water body discharge pipe.

[0050] In the above technical solution, a complete municipal roadway pollutant treatment process is formed through the synergistic effect of a bar screen, a biofilm reactor, an ecological filter, and an ultraviolet disinfection device. The bar screen effectively intercepts large particles and sludge, preventing them from entering subsequent treatment units; the biofilm reactor utilizes the biofilm on the combined packing layer to degrade pollutants; the ecological filter further purifies the water quality through multiple layers of filter media and plants; and the ultraviolet disinfection device kills pathogens, ensuring that the effluent meets standards. This system design improves pollutant removal efficiency, ensures stable system operation, and effectively protects the natural aquatic environment.

[0051] Specifically, the bar screen can be installed 1.5-2.0 meters downstream of the road rainwater collection inlet. The tilt angle of the inclined bar can be 60-75 degrees, the bar spacing can be 10-15 mm, and the material can be 304 stainless steel. The volume of the sedimentation tank can be designed to be 0.3-0.5 cubic meters, and the bottom sludge discharge pipe can be a DN150 HDPE pipe. The end of the sludge discharge pipe can be connected to the inlet of the sludge treatment equipment, which can be a screw press sludge dewatering machine. During assembly, the inlet of the bar screen should be connected to the flange of the outlet pipe of the rainwater collection inlet, and the bottom slope of the sedimentation tank should be set at 3%-5%. During operation, when rainwater runoff passes through the inclined bar, suspended solids with a particle size greater than 15 mm are intercepted, fine particles settle in the sedimentation tank, and the sludge in the sedimentation tank is discharged through the sludge discharge pipe after reaching the set liquid level. The bar screen can effectively intercept large particulate pollutants and achieve automatic sludge cleaning.

[0052] The inlet of the biofilm reactor can be located on the side wall of the tank, 0.8-1.0 meters from the bottom. The effective water depth of the tank can be designed to be 1.8-2.0 meters. The thickness of the volcanic rock packing layer can be 0.5-0.6 meters, the ceramsite packing layer 0.4-0.5 meters, and the polyurethane biological carrier layer 0.3-0.4 meters. The aeration system can use cyclone aerators with a 200 mm diameter aeration disc and 2 mm aeration holes. The main aeration pipe can be made of UPVC. During assembly, the bottom of the combined packing layer should be 0.3-0.4 meters from the bottom of the tank, and the aeration network should be evenly distributed below the combined packing layer. During operation, as wastewater passes through the combined packing layer, the biofilm removes organic matter through adsorption and degradation, while the aeration system provides dissolved oxygen and creates hydraulic disturbance. The biofilm reactor enhances the metabolic activity of microorganisms and improves the efficiency of organic matter degradation.

[0053] For ecological filters, the gravel layer can be made of limestone crushed stone with a particle size of 25-30 mm, and the zeolite layer can be made of clinoptilolite with a particle size of 6-8 mm. The humus in the planting layer can be taken from garden waste compost. The spacing between reeds, calamus, and irises can be set at 0.3-0.5 meters. The perforated water collection pipe can be made of HDPE porous pipe with an opening diameter of 8 mm, wrapped with a geotextile filter layer. During assembly, the bottom of the gravel layer should be 0.2-0.3 meters below the bottom of the filter bed, and the centerline of the perforated water collection pipe should be 0.1-0.15 meters above the bottom of the filter bed. During operation, wastewater is filtered and adsorbed by the gravel layer, and the plant roots absorb nitrogen and phosphorus pollutants. The purified water is collected and discharged through the water collection pipe. Ecological filters can achieve deep removal of pollutants and ecological restoration.

[0054] The ultraviolet (UV) disinfection device can use low-pressure, high-intensity mercury lamps, with a lamp power of 80-100W per lamp. The number of lamps should be 4-6 per 100 m³ / h of treatment capacity. The device casing can be made of 316L stainless steel, and the water flow channel width should be 0.3-0.4 meters. During assembly, the UV disinfection device should be installed at the end of the ecological filter's outlet channel, with the inlet connected to the perforated collection pipe outlet via a flange. During operation, purified water flows through the disinfection chamber at a velocity of 0.3-0.5 m / s, and the UV dose is controlled at 30-40 mJ / cm². The UV disinfection device can effectively inactivate pathogenic microorganisms in the water.

[0055] In another technical solution, a transition buffer layer 24 is provided between the volcanic rock packing layer and the ceramsite packing layer of the combined packing layer. The transition buffer layer 24 is composed of zeolite particles with a particle size of 8-10 mm and a calcium ion exchange capacity of ≥200 mg / g, and has a thickness of 50-80 mm.

[0056] The polyurethane biocarrier layer has a through-hole microporous channel with a diameter of 1-1.5 mm. The inner wall of the microporous channel is coated with a nano-titanium dioxide photocatalytic coating with a thickness of 10-20 μm. The thickness of the polyurethane biocarrier layer is 0.4-0.6 μm, and the porosity of its microporous channel is ≥85%, and the wet compression resilience is ≥90%.

[0057] The aeration pipe 25 of the aeration system forms a swirling aeration structure at the bottom of the combined packing layer, and the aeration holes of the aeration system are tilted at an angle of 30-45 degrees.

[0058] In the above technical solution, the transition buffer layer ensures a smoother water flow transition between different fillers in the combined packing layer, avoiding uneven packing distribution caused by water flow impact and improving treatment efficiency. The microporous channels and nano-titanium dioxide photocatalytic coating of the polyurethane biocarrier layer increase the bio-attachment area and photocatalytic reaction, which is beneficial for microbial growth and pollutant degradation. The swirling aeration structure and inclined aeration holes improve aeration efficiency, ensuring uniform dissolved oxygen distribution, promoting biofilm growth and metabolism, and further enhancing pollutant removal capacity.

[0059] Specifically, the zeolite particles in the transition buffer layer can be selected with a particle size of 9-10 mm and a calcium ion exchange capacity of 220-250 mg / g. The material can be clinoptilolite or mordenite, and the thickness can be set to 60-70 mm. This transition buffer layer can be installed between the volcanic rock packing layer and the ceramsite packing layer, with the interlayer gap controlled at 5-8 mm. During operation, when water flows through the interface of packing particles of different sizes, the transition buffer layer adsorbs ammonium nitrogen through calcium ion exchange, while simultaneously buffering the water flow velocity to prevent cross-contamination between packing layers. A biofilm can form on the surface of the zeolite particles in the transition buffer layer, creating a synergistic treatment effect with the upper and lower packing layers and enhancing denitrification performance.

[0060] The polyurethane biocarrier can utilize a continuous microporous structure with a pore size of 1.2-1.4 mm, and the inner walls of the microporous channels can be coated with a 15 μm thick nano-titanium dioxide coating. The carrier layer thickness can be 0.45-0.55 meters, and the porosity can be controlled within the range of 87-89%. Hydrophilic polyurethane foam can be used as the material, with a wet compression resilience of 92-95%. During assembly, the top of the polyurethane biocarrier should maintain a clearance of 0.2-0.3 meters from the water surface. During operation, the microporous channels create turbulence, enhancing mass transfer efficiency, and the nano-titanium dioxide coating generates hydroxyl radicals under visible light, strengthening the oxidative decomposition of organic matter. The elastic characteristics of the polyurethane material prevent structural collapse during long-term operation.

[0061] The aeration system is optimized with DN50 UPVC pipes for the aeration pipes. The aeration holes can be angled at 35-40 degrees and have a diameter of 2.5-3.0 mm. The swirl aeration structure can be designed in a ring arrangement, with aeration branch pipe spacing of 200-220 mm. During assembly, the centerline of the aeration pipe can be 150-180 mm from the bottom of the packing layer. During operation, the angled aeration holes generate a swirling water flow, causing the air-water mixture to rise along a spiral trajectory, extending the bubble residence time to 8-12 seconds. This structure improves the uniformity of dissolved oxygen distribution, achieving an oxygen transfer efficiency of 6.5-7.2 kgO per unit of energy consumption. 2 / kWh.

[0062] The transition buffer layer smooths out water flow shear force and enhances denitrification capacity; the polyurethane carrier layer improves organic matter removal through physical structure and photocatalysis; and the swirl aeration structure optimizes oxygen mass transfer efficiency. The combination of these three elements improves system operational stability, reduces the risk of packing blockage, and adapts to fluctuating water quality conditions.

[0063] In another technical solution, the humus planting layer comprises the following components blended in a specific mass ratio:

[0064] The soil contains 60%-70% humus, with an organic matter content ≥25% and a pH of 6.0-7.5.

[0065] 15%-20% modified biochar particles, particle size 2-4mm, specific surface area ≥500m² / g, surface loading of 3%-5% Fe-Mn oxide by mass fraction;

[0066] 10%-15% diatomite-zeolite composite particles, particle size 1-3mm, calcium ion exchange capacity ≥180mg / g;

[0067] 5%-8% slow-release microbial inoculant granules, including nitrifying bacteria, denitrifying bacteria, and plant rhizosphere growth-promoting bacteria, with a content ≥1×10 6 CFU / g, ≥5×10 5 CFU / g, ≥2×10 6 CFU / g;

[0068] The humus planting layer is divided into a top layer and a bottom layer from top to bottom. The top layer is 50-80mm thick and includes a mixture of humus and modified biochar in a 7:3 mass ratio. Reeds, calamus and irises are planted in the top layer, with the three plants arranged at a 2:1:1 ratio. Spiral drainage channels are provided in the root zone. The spiral drainage channels are 20-30mm deep and the channel spacing is 80-100mm.

[0069] The bottom layer is 150-220mm thick and consists of a mixture of humus and diatomaceous earth-zeolite composite particles in a 6:4 mass ratio. The bottom layer is pre-embedded with permeable ceramic granule pipes with a diameter of 10-15mm. The horizontal spacing of the permeable ceramic granule pipes is 200-250mm and the vertical spacing is 100-150mm.

[0070] In the above technical solution, the compound components and layered structure of the humus planting layer fully leverage the synergistic effects of plants, microorganisms, and filter media. Modified biochar particles, diatomaceous earth-zeolite composite particles, and slow-release microbial inoculant particles provide a favorable environment for plant growth and microbial metabolism, enhancing the adsorption and degradation capacity of pollutants. The spiral-shaped drainage channels on the surface facilitate water infiltration and plant root growth, while the permeable ceramsite pipes at the bottom ensure uniform water distribution and smooth drainage, thereby enhancing the purification effect of the ecological filter.

[0071] Specifically, the material composition for the humus planting layer is as follows: The humus can be garden humus with an organic matter content of 28%-30%, and the pH value can be controlled between 6.5 and 7.0. Modified biochar granules can be made from coconut shell-based materials, with a surface-loaded Fe-Mn oxide mass fraction of 3.8%-4.2% and a specific surface area of ​​550-600 m² / g. Diatomaceous earth-zeolite composite granules can be pre-formed granules mixed and granulated at a 1:1 mass ratio, with a calcium ion exchange capacity of 190-200 mg / g. Slow-release bacterial agent granules can be made from nitrifying bacteria with an encapsulation density of ≥1.2 × 10⁻⁶. 6CFU / g, denitrifying bacteria ≥6×10 5 Commercially available slow-release microbial preparations at CFU / g. When mixing the components in a mixer according to the mass ratio, the mixing time can be set to 15-20 minutes, and the stirring speed can be selected to be 30-40 rpm. During material assembly, the surface mixture covers the bottom mixture, with a 10-15 mm thick fine sand transition layer between the two.

[0072] Surface Plant Configuration and Water Diversion Structure: Reeds, calamus, and irises can be planted at a ratio of 2:1:1, spaced 60-80cm apart. The water diversion channels can be designed as spirals, with a depth of 25mm, a width of 15mm, and a spacing of 90mm between adjacent spirals. The spiral channels extend outwards clockwise or counterclockwise from the plant roots, forming single or multiple spiral paths. The starting point of the channel is located within 50-80mm of the plant roots, with a spiral extension angle of 120-150 degrees. The channels guide water flow to form vortexes in the root zone, extending the hydraulic residence time to 8-10 minutes. Plant roots grow downwards along the channels, and the channel structure prevents surface soil compaction while enhancing root-to-pollutant contact efficiency. 3D-printed ABS templates can be used for the channel molds, pressed into the planting layer surface during construction to form the trench structure. During assembly, the starting point of the guide channel is located within 50mm around the plant roots, and the spiral extension angle can be set to 120-150 degrees. As the plant roots grow downwards along the guide channel, the channel structure can guide the water flow to form a vortex flow in the root zone, extending the hydraulic residence time to 8-10 minutes, while preventing the surface soil from compacting.

[0073] Layout of the bottom layer of permeable ceramsite pipes: The permeable ceramsite pipes can be porous ceramsite pipes with an outer diameter of 12mm and a wall thickness of 3mm, with an open area ratio of 20%-25%. The center-to-center spacing of the horizontally arranged ceramsite pipes can be set to 220-230mm, and the vertical layer spacing can be 120-130mm. The ceramsite pipes can be prefabricated into standard pipe sections with a length of 800-1000mm, and a 5mm expansion joint can be reserved at the pipe section connections. During assembly, the bottom layer of mixed material is filled in layers, with a layer of ceramsite pipes placed after every 50mm of thickness. The longitudinal slope of the pipe body can be set at 2%-3%. The permeable ceramsite pipes and the upper-layer diversion channels form a three-dimensional diversion network. When the hydraulic load reaches 1.2m³ / (m²·h), the system permeability coefficient can be maintained in the range of 0.8-1.2cm / s.

[0074] The humus components remove pollutants through a synergistic effect of physical adsorption and biodegradation, while the surface drainage structure enhances the contact efficiency between plant roots and pollutants. The underlying permeable pipe network ensures the system's permeability. The combination of these three elements enables long-term stable operation of the planting layer, effectively improving nitrogen and phosphorus removal capacity while preventing clogging of the filler layer.

[0075] In another technical solution, the perforated water collection pipe is surrounded by a volcanic rock particle filter layer with a particle size of 3-5mm, the thickness of the volcanic rock particle filter layer is 80-100mm, and the porosity of the volcanic rock particles is 45%-55%.

[0076] The perforated water collection pipe is divided into upper and lower layers. The upper layer perforated water collection pipe has an opening direction of 15%-18% and an opening rate of 15%-18%. The lower layer perforated water collection pipe has an opening direction of 12%-15% and an opening rate of 12%-15%. The distance between the upper and lower layers of perforated water collection pipes is 200-250mm.

[0077] In the above technical solution, the volcanic rock particle filter layer protects and filters the perforated water collection pipe, preventing impurities from clogging the pipe and improving water collection efficiency. The different opening directions and opening rates of the upper and lower perforated water collection pipes enable more comprehensive collection of purified water from the ecological filter, resulting in more uniform water collection and further improving the water purification effect.

[0078] Specifically, the volcanic rock particle filter layer configuration is as follows: The volcanic rock particles can be selected as basalt gravel with a particle size of 4-5mm, and the porosity can be controlled within the range of 48%-52%. The thickness of the volcanic rock particle filter layer can be set to 85-90mm. During the construction of the wrapping layer, a geotextile-sewn bag structure is used, and the bag body can be made of 200g / m² polyester filament geotextile. During assembly, the volcanic rock filter layer is tightly fitted to the outer wall of the perforated water collection pipe, and the outer edge of the volcanic rock particle filter layer maintains a gap of 50-80mm from the side wall of the ecological filter pool. During operation, when purified water flows through the zeolite layer and infiltrates, the volcanic rock particle filter layer can intercept suspended solids with a particle size >0.5mm, while simultaneously degrading dissolved organic matter through the surface biofilm. The pore structure of the volcanic rock particle filter layer allows the water flow velocity to remain stable at 0.6-0.8m / h, and it can still maintain more than 85% of the initial permeability coefficient after 90 days of operation.

[0079] Double-layer perforated water collection pipe structure: The upper perforated water collection pipe can be made of HDPE porous pipe with a perforation diameter of 6mm, and the perforation rate can be set to 16%-17%. The holes can be arranged in a staggered pattern, and the longitudinal hole spacing can be set to 40-45mm. The lower perforated water collection pipe can be made of UPVC porous pipe with a perforation diameter of 5mm, and the perforation rate can be set to 13%-14%. The holes are arranged in a straight line, and the longitudinal hole spacing can be set to 50-55mm. The distance between the upper and lower pipes can be controlled at 220-230mm, and the bottom of the lower perforated water collection pipe should maintain a space of 100-120mm from the bottom of the pool. During assembly, the center line of the perforation of the upper perforated water collection pipe should be at a 15-degree angle to the horizontal plane, and the center line of the perforation of the lower perforated water collection pipe should be at a 20-degree angle to the horizontal plane. During operation, the upper perforated water collection pipe mainly collects clean water filtered by the zeolite layer, while the lower perforated water collection pipe simultaneously discharges tiny particles deposited in the gravel layer. When the instantaneous flow rate of the system reaches 1.5 times the design value, the double-layer structure can reduce the water level fluctuation to within ±50mm.

[0080] The effect of layered opening direction on preventing clogging and ensuring uniform water collection:

[0081] Upper perforated water collection pipe, anti-clogging: With its upward-opening design, it prioritizes the collection of clean water that has been filtered by the upper filter media (such as zeolite layer), avoiding the intake of suspended particles or sediments that may accumulate at the bottom, thereby reducing the risk of the holes being clogged.

[0082] Uniformity of water collection: The upward-angled opening causes the water to enter the water collection pipe along a gentle path, reducing sudden changes in local flow velocity and helping to achieve uniform water collection on the water surface, avoiding regional overload or turbulence caused by concentrated water flow.

[0083] The lower perforated water collection pipe prevents clogging: the downward opening can actively discharge the tiny particles deposited in the bottom filter material (such as gravel layer), and guide the impurities away from the water collection pipe area by gravity, preventing the holes from being blocked by long-term siltation.

[0084] Uniformity of water collection: The downward-angled opening promotes the smooth rise of water from the bottom to the water collection pipe, reducing direct impact or "short circuit" phenomenon of water flow and ensuring a balanced distribution of water flow in all areas of the filter cross-section.

[0085] The upper and lower perforated water collection pipes work in tandem: the perforation directions of the upper and lower layers are complementary. The upper layer focuses on collecting clean water flow, while the lower layer is responsible for the dynamic removal of sediment. Together, they form a gradient interception mechanism. Through this layered design, the system can adapt to different flow conditions, maintaining stable water collection efficiency even under high loads, while reducing the decline in permeability caused by localized clogging of the filter media. This solution optimizes the physical structure, balancing anti-clogging and water collection uniformity requirements, and improves the long-term operational reliability of the system without relying on complex control systems.

[0086] The volcanic rock filter layer effectively prevents clogging of the perforated water collection pipe holes, and the double-layer perforated pipe structure enables graded water collection and sludge removal. Together, these features enhance the operational stability of the ecological filter, maintaining stable effluent quality even under high hydraulic loads during heavy rains, while extending the filter's maintenance and cleaning cycle to 12-18 months.

[0087] In another technical solution, a backwashing system is also included, which includes a municipal water supply pipe and an ultraviolet disinfection return water pipe connected by a three-way valve. The backwash water is injected into the perforated water collection pipe in reverse through the backwashing branch pipe. The end of the backwashing branch pipe is connected to the sludge collection tank 35. The bottom of the sludge collection tank 35 is connected to the sludge treatment equipment through a screw conveyor.

[0088] The perforated water collection pipe is connected to a backwash branch pipe at its end. A pressure sensor is installed on the backwash branch pipe. When the pressure difference between the inside and outside of the water collection pipe exceeds the set threshold, the backwash mode is triggered.

[0089] In the above technical solution, the backwashing system solves the problem of clogging in the water collection pipe and filter media layer, ensuring the long-term stable operation of the system. When the pressure sensor detects that the pressure difference between the inside and outside of the water collection pipe exceeds the threshold, the backwashing mode is automatically triggered, using municipal water supply or ultraviolet disinfection return water for backwashing, flushing the sludge into the sludge collection tank, and then transporting it to the sludge treatment equipment by a screw conveyor, realizing timely sludge treatment and automated system operation.

[0090] Specifically, the backwashing system piping configuration is as follows: The three-way valve can be a DN100 pneumatic butterfly valve type switching device, and the valve body material can be nickel-plated brass. The backwashing branch pipe can be a DN80 HDPE pipe, and the working pressure can be set to 0.4-0.6MPa. The sludge collection tank can be a PE material tank with a volume of 2-3 cubic meters, and the screw conveyor can be a shaftless screw conveyor with a diameter of 300mm, and the conveying speed can be adjusted to 2-3m / min. During assembly, the three-way valve can be installed at the inlet end of the backwashing branch pipe, 1.2-1.5 meters away from the nearest perforated water collection pipe interface. During operation, when switching to backwash mode, pressurized water flows backward into the water collection pipe at a flow rate of 1.2-1.5m / s, and the flushing intensity can be controlled at 12-15L / (m²·h), continuing for 8-10 minutes before switching back to normal operation mode.

[0091] Differential pressure trigger control logic: The pressure sensor can be a piezoresistive sensor with a range of 0-100 kPa, and the installation position can be set 0.5-0.8 meters from the end of the backwash branch pipe. The differential pressure threshold can be set to 20 kPa. When the differential pressure inside and outside the collection pipe exceeds this value and lasts for 120 seconds, the PLC controller can start the backwash program. During assembly, the pressure sensor probe can be embedded at 1 / 2 of the pipe wall thickness, and the signal line is connected to the control cabinet through a waterproof connector. During operation, when the filter layer becomes clogged, causing increased water flow resistance, the backwash system automatically switches the water source for backwashing. The sludge carried by the backwash water enters the collection tank and is then conveyed to the dewatering equipment by a screw conveyor at a speed of 45-50 rpm. The drainage volume of each backwash can be controlled at 3%-5% of the total system water volume.

[0092] The backwashing pipeline configuration enables the system's reverse cleaning function, and the differential pressure triggering mechanism ensures timely removal of blockages in the packing layer. Together, these features maintain the stable permeability of the ecological filter, reduce the frequency of manual maintenance, and effectively prevent system performance degradation caused by excessive biofilm accumulation during long-term operation.

[0093] In another technical solution, the inlet of the ultraviolet disinfection device is equipped with a turbidity sensor and a flow meter. When the turbidity is greater than 5 NTU or the flow exceeds the design value by 20%, the PLC controller will synchronously control the lamp power of the ultraviolet disinfection device to increase to 100%-110% and operate at overpower for no more than 30 minutes at a time.

[0094] An ultraviolet intensity monitoring probe is installed at the end of the ultraviolet disinfection device. When the detected dose is <30mJ / cm², the water flow residence time is extended to 1.2-1.5 times the original value.

[0095] In the above technical solution, the ultraviolet disinfection device automatically adjusts the lamp power and water residence time according to changes in turbidity and flow rate, ensuring good disinfection results under different water quality and flow conditions, and avoiding problems such as incomplete disinfection or energy waste. When the turbidity is high or the flow rate is large, the lamp power is increased; when the ultraviolet intensity is insufficient, the water residence time is extended, ensuring the hygiene and safety of the effluent.

[0096] Specifically, the UV power dynamic adjustment mechanism is as follows: The turbidity sensor can be an online diffused light turbidity meter with a range of 0-20 NTU, installed 0.8-1.2 meters upstream of the UV disinfection device inlet in a straight pipe section. A DN150 electromagnetic flow meter can be used, with measurement accuracy controlled within ±1.5%FS. The PLC controller can incorporate a two-level control strategy: when turbidity > 5 NTU or instantaneous flow exceeds the design value by 20% (e.g., the trigger threshold is 120 m³ / h when the design flow is 100 m³ / h), the UV lamp power can be increased to 105%-108% of the rated power, and the over-power operation duration can be set to 25-28 minutes. During assembly, the turbidity sensor probe can be inserted to a depth of 1 / 3 below the pipe centerline, and the straight pipe section length before and after the flow meter should maintain the requirement of 10D upstream and 5D downstream (D being the pipe diameter). During operation, when water quality deteriorates or water volume suddenly increases, the ultraviolet disinfection device automatically increases the ultraviolet intensity to 30-35 mJ / cm² to ensure stable disinfection effect.

[0097] Ultraviolet (UV) Dosage Compensation Control: The UV intensity monitoring probe can be a 254nm UV photosensitive sensor with a range of 0-50mJ / cm². The probe can be installed on the outside of the quartz sleeve at the outlet of the UV disinfection device, 150-180mm from the last row of lamps. When the detected actual dose is <30mJ / cm², the PLC can control the opening of the outlet electric valve from fully open to 75%-80%, extending the water residence time from the baseline of 8 seconds to 9.6-10 seconds. During assembly, the UV intensity monitoring probe protective cover can be made of quartz glass with a transmittance of over 90%. During operation, when the lamps age or the water transmittance decreases, the disinfection dose is compensated by extending the contact time. During the compensation phase, the water flow velocity can be reduced to 0.25-0.3m / s to ensure that the cumulative UV dose maintains an effective disinfection level.

[0098] The power regulation mechanism can cope with changes in disinfection requirements caused by fluctuations in influent water quality, while the dosage compensation control ensures the continuous disinfection efficiency of the ultraviolet system. Working together, these two mechanisms can adapt to high-turbidity wastewater during the rainy season and conditions of equipment performance degradation without increasing equipment capacity, effectively maintaining compliance with water microbiological standards for discharge.

[0099] In another technical solution, an ultrasonic level sensor is installed on the side wall of the sedimentation tank. The height of the probe of the ultrasonic level sensor from the bottom of the sedimentation tank is 2 / 3 to 3 / 4 of the depth of the sedimentation tank, and the detection is performed at a set detection frequency.

[0100] The sludge discharge pipe inlet is equipped with a pneumatic knife gate valve with a gate thickness of 8-10mm;

[0101] The ultrasonic level sensor is connected to the PLC controller. When the sludge layer height is detected to be greater than 1 / 2 of the sedimentation tank depth for three consecutive times, the PLC controller controls the pneumatic knife gate valve to fully open within 15 seconds to discharge sludge until the ultrasonic level sensor detects that the sludge layer height is less than the set low threshold. At this point, the pneumatic knife gate valve closes, the sludge discharge pipe outlet is connected to the screw conveyor inlet, and the screw conveyor outlet is connected to the sludge treatment equipment receiving bin.

[0102] In the above technical solution, the automated control of sludge discharge from the sedimentation tank is achieved through the cooperation of an ultrasonic level sensor and a PLC controller. When the sludge layer height exceeds the set value, the pneumatic knife gate valve automatically opens to discharge sludge, and automatically closes after the sludge reaches the low threshold level. This ensures the normal operation of the bar screen interception device, avoids the impact of sludge accumulation on the system, and improves the efficiency of sludge treatment.

[0103] Specifically, the ultrasonic level sensor can be installed and monitored at a height of 0.9-1.1 meters from the bottom of the sedimentation tank on the side wall, corresponding to two-thirds to three-quarters of the total depth of the sedimentation tank. A pulse-type ultrasonic probe with a range of 0-2 meters can be used as the ultrasonic level sensor, and the detection frequency can be set to cycle every 10 minutes. The protective cover for the ultrasonic level sensor probe can be made of PTFE material, with acid and alkali resistance meeting pH 3-11 environmental requirements. During assembly, the ultrasonic level sensor flange is fixed to the tank wall opening with four bolts, and the sealing gasket can be made of EPDM rubber. During operation, when the sludge layer interface height exceeds 0.6 meters three times consecutively, the system determines it to be in a high-level alarm state and triggers the sludge discharge procedure.

[0104] The pneumatic gate valve can be made of 304 stainless steel with a nominal diameter of 150mm and a gate thickness of 9mm. The actuator can be a linear cylinder with a stroke time of 15 seconds. The sludge discharge pipe can be made of DN150 ultra-high molecular weight polyethylene pipe, and the screw conveyor can be a horizontal shaftless model with a power of 5.5kW. During assembly, the gate valve can be installed at the beginning of the sludge discharge pipe, 0.3-0.5 meters from the bottom outlet of the sedimentation tank, with the valve body axis tilted downwards at a 3-5 degree angle to the horizontal plane. During operation, when the PLC controller issues a sludge discharge command, the cylinder completes a full opening action within 12-15 seconds, and the sludge enters the conveyor at a flow rate of 0.8-1.2m / s until the liquid level drops to the 0.3-meter threshold, at which point the valve closes.

[0105] The PLC controller of the sludge treatment linkage control system can be equipped with two-level delay protection, automatically cutting off the air supply when the cumulative sludge discharge time exceeds 30 minutes. The screw conveyor speed can be set to 40-45 rpm, with a conveying capacity matching a sludge discharge flow rate of 10-12 m³ / h. During assembly, the conveyor inlet and sludge discharge pipe outlet are flexibly connected, allowing a 50mm height difference to facilitate material gravity flow. During operation, the sludge is squeezed and dewatered by the conveyor, forming a sludge cake with a moisture content of 75-80%, which falls into the sludge collection box through a chute. The treatment cycle is synchronized with the sludge dredging requirements of the sedimentation tank.

[0106] The liquid level monitoring system enables precise sensing of sludge deposition status, and the coordinated control of pneumatic valves and conveying equipment ensures timely dredging. This configuration reduces the frequency of manual inspections, avoids the risk of system blockage caused by excessive sludge accumulation in the sedimentation tank, and ensures that sludge discharge operations match the capacity of downstream processing equipment.

[0107] In another technical solution, three dissolved oxygen sensors are spaced apart along the water flow direction in the biofilm reaction tank, located 200mm above the bottom of the combined packing layer, 150mm below the middle and top of the combined packing layer, respectively.

[0108] The blower of the aeration system is equipped with a frequency converter with an output frequency of 30-50Hz. The frequency converter is connected to the PLC controller via a 4-20mA signal.

[0109] The PLC controller has a built-in segmented control algorithm. When the dissolved oxygen sensor values ​​of any two sensors are <2.5mg / L, the blower frequency is increased to 40-45Hz. When the dissolved oxygen sensor values ​​of all three sensors are >3.0mg / L, the frequency is reduced to 35-38Hz.

[0110] The blower outlet pipe is equipped with a bypass pressure relief branch pipe with a solenoid valve. When the aeration intensity is >1.2m³ / (m²·h) for 5 minutes, the solenoid valve opens to 10%-15% of its opening.

[0111] In the above technical solution, the dissolved oxygen sensor in the biofilm reactor, the frequency converter of the aeration system, and the segmented control algorithm of the PLC controller can accurately control the dissolved oxygen concentration. Based on real-time data from the dissolved oxygen sensor, the frequency of the blower is automatically adjusted to maintain the dissolved oxygen concentration within a suitable range for biofilm growth and pollutant degradation. The bypass pressure relief branch pipe ensures the safe operation of the aeration system and avoids damage to the system caused by excessive aeration intensity.

[0112] Specifically, the dissolved oxygen sensors can be positioned on the sidewall of the biofilm reactor at heights of 0.8 meters, 1.2 meters, and 1.7 meters from the bottom, corresponding to positions 200 mm above the bottom, 150 mm below the middle, and 150 mm below the top of the combined packing layer. Fluorescent dissolved oxygen probes with a range of 0-10 mg / L and an IP68 protection rating can be used. During assembly, the tip of the dissolved oxygen sensor probe should be 50-80 mm from the inner side of the reactor wall, with the probe axis at a 15-degree angle to the horizontal plane to avoid direct impact from air bubbles. During operation, the three dissolved oxygen sensor probes monitor the dissolved oxygen concentration at different depths. When the bottom sensor value drops below 2.5 mg / L, an enhanced aeration mode is triggered.

[0113] The frequency converter can be a vector frequency converter with a 4-20mA signal input, and the output frequency adjustment range can be set to 30-50Hz. A Roots blower can be selected, with a rated air volume matching 4.5m³ / min. During assembly, the frequency converter can be installed in a control cabinet 3-5 meters away from the blower, and a 3-core 4mm² copper shielded cable can be used for the power cable. During operation, when any two dissolved oxygen sensor values ​​remain below the 2.5mg / L threshold for 60 seconds, the PLC output signal causes the frequency converter frequency to increase from the reference value of 35Hz to 42Hz, the aeration rate to increase from 0.9m³ / (m²·h) to 1.1m³ / (m²·h), and the oxygen transfer efficiency to increase to 7.2kgO2 / kWh.

[0114] The bypass pressure relief branch pipe can be a DN80 UPVC pipe, and the solenoid valve can be a normally closed pilot-operated solenoid valve with a nominal diameter of 50mm. A silencer can be connected to the end of the pressure relief branch pipe; the silencer can be made of fiberglass with a honeycomb structure. During assembly, the branch pipe interface can be located 1.2-1.5 meters above the blower's outlet pipe, and the solenoid valve actuator can be installed vertically upwards. During operation, when the aeration intensity exceeds 1.2 m³ / (m²·h) for 300 seconds, the solenoid valve opens 12% to relieve pressure, reducing the system pressure from 65 kPa to 58 kPa to prevent blower overload.

[0115] Multi-point dissolved oxygen monitoring enables comprehensive oxygen concentration control in the reaction tank, while the synergistic effect of frequency conversion regulation and pressure relief protection ensures the safe and economical operation of the aeration system. This configuration can quickly respond to changes in dissolved oxygen demand when water quality fluctuates, preventing the biofilm from losing activity due to hypoxia or over-aeration, and reducing equipment failure rate.

[0116] <Experiment>

[0117] 1. Experimental Objective

[0118] The adaptability of reed (Phragmites australis), sweet flag (Acorus calamus), and iris (Irispseudacorus) to a simulated ecological filter environment was tested, and survival rate and growth status data were obtained for 6 consecutive months.

[0119] 2. Test materials

[0120] Plant samples: Select healthy, disease-free, one-year-old seedlings with a height of 40±5cm for reeds, a crown width of 25±3cm for calamus, and ≥4 leaves for irises.

[0121] Planting substrate: Prepare a humus planting layer according to the following ratio (65% humus + 18% modified biochar + 14% diatomaceous earth-zeolite composite particles + 3% slow-release bacterial agent).

[0122] Control substrate: ordinary garden soil (pH 7.1, organic matter content 8%)

[0123] 3. Test apparatus

[0124] Construct 6 sets of simulated ecological filter beds, each 1.2m × 0.6m × 0.8m in size:

[0125] Filter layer structure: bottom layer 30cm gravel (particle size 25-30mm), middle layer 20cm zeolite (particle size 6-8mm), top layer 25cm test / control matrix;

[0126] Hydraulic system: perforated water distribution pipe (flow rate 0.8 m³ / d), water collection pipe, circulating pump;

[0127] Environmental control: natural light + supplemental lighting (light intensity 8000-10000 lux, 12 hours per day), temperature maintained at 18-28℃;

[0128] 4. Test Methods

[0129] Planting arrangement: Plant in each pond at a ratio of 2:1:1 (8 reeds + 4 calamus + 4 irises), with a plant spacing of 40cm;

[0130] Water level control: Maintain a water depth of 5-8 cm below the substrate surface;

[0131] Nutrient supply: Inject simulated runoff water weekly (COD 80-120 mg / L, NH3-N 8-12 mg / L, TP 1.5-2.0 mg / L).

[0132] Data collection:

[0133] Monthly monitoring: number of surviving plants, plant height / crown width growth rate, root length;

[0134] Test every two months: chlorophyll content (SPAD value) and root activity (TTC method);

[0135] Environmental monitoring: water temperature, pH, dissolved oxygen (recorded daily);

[0136] 5. Data Analysis

[0137] Survival rate calculation: (Number of surviving plants / Initial number of plants) × 100%

[0138] Growth indicator: ΔH = (Final plant height - Initial plant height) / Initial plant height × 100%

[0139] Significance test: One-way ANOVA was performed using SPSS 26 (α=0.05).

[0140] 6. Key Experimental Results

[0141] Table 1 Key Experimental Data

[0142]

[0143] Note: Data from the control group showed that the survival rate, growth rate, and physiological indicators of plants in ordinary garden soil were significantly lower than those in the experimental group (P<0.05), further verifying the superiority of the humus soil planting layer ratio.

[0144] 7. Summary of Experimental Results

[0145] 7.1 Plant survival performance: Reed, sweet flag, and iris all showed high adaptability in the simulated ecological filter environment. During the 6-month experimental period, reed had the highest survival rate (>90%), while sweet flag and iris both had survival rates >85%, significantly better than the ordinary garden soil control group (survival rate <60%). Plant mortality mainly occurred in the early stage of the experiment (first 30 days), and the survival status tended to stabilize in the later stage.

[0146] 7.2 Growth Characteristics Analysis:

[0147] Reeds: They exhibited the greatest increase in plant height (more than twice the initial value), outstanding longitudinal root extension ability (average length > 55cm), and demonstrated strong water absorption and flood resistance.

[0148] Sweet flag: It has the fastest crown expansion rate (average monthly growth of 12-15cm) and a well-developed lateral root system (the number of tillers increases by 3-4 times), making it suitable for intercepting surface pollutants;

[0149] Iris: It has the highest chlorophyll content (SPAD value > 45) and significant root biomass accumulation (dry weight increased by 4.2 times compared to the initial value), indicating that it has better photosynthetic and nutrient absorption efficiency.

[0150] 7.3 Environmental tolerance: No plants showed symptoms of stress such as yellowing leaves and root rot under simulated runoff water quality (COD≤120mg / L, NH3-N≤12mg / L);

[0151] Root activity (TTC reducing power ≥ 0.8 mg / g·h) remained consistently active, confirming the stability of the microbial-plant synergistic effect;

[0152] During the low-temperature period of winter (15-18℃), the growth rate decreased by 20%-30%, but no frost damage or dormancy occurred.

[0153] Experiments demonstrate the rationality of the humus planting layer ratio in this application, and show that the plant roots, drainage channel structure, and permeable ceramsite pipes form an effective synergy.

[0154] The deep root system of reeds enhances the permeability of the underlying substrate, the fibrous root system of calamus promotes the interception of surface pollutants, and the high metabolic activity of iris enhances the absorption of nitrogen and phosphorus.

[0155] All three plant species met the requirement of long-term survival for 6 months in the simulation system. Their differentiated growth characteristics can be adapted to the multi-level purification function of the ecological filter, providing a reliable biological carrier for the long-term operation of the system.

[0156] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A biological-ecological synergistic purification system for roadside pollutants in municipal roads, characterized in that, include: A bar screen interception device is located downstream of a road rainwater collection inlet. The bar screen interception device includes an inclined bar screen with a sedimentation tank at the bottom of the inclined bar screen. The bottom of the sedimentation tank is connected to a sludge discharge pipe, and the end of the sludge discharge pipe is connected to a sludge treatment device. The biofilm reactor has its inlet connected to the outlet of a bar screen. The reactor contains a combined packing layer, which, from bottom to top, consists of a volcanic rock packing layer with a particle size of 10-15 mm, a ceramic granule packing layer with a particle size of 5-8 mm, and a packing layer with a specific surface area greater than 800 m². 2 / m 3 The polyurethane biocarrier layer and the combined packing layer have a total thickness of 1.2-1.5m. An aeration system is installed at the bottom of the biofilm reactor, with an output intensity of 0.8-1.2m. 3 / (m 2 ·h); The ecological filter has its inlet connected to the outlet of the biofilm reactor. From bottom to top, the ecological filter is equipped with a gravel layer of 0.5-0.8m thickness, a zeolite layer of 0.3-0.5m thickness, and a humus planting layer of 0.2-0.3m thickness. The gravel layer has a particle size of 20-30mm, the zeolite layer has a particle size of 5-10mm, and the humus planting layer is planted with reeds, calamus, and irises. The bottom of the ecological filter is equipped with a perforated water collection pipe with an opening rate of 15%-20%. The ultraviolet disinfection device is located at the outlet of the ecological filter pond, and the outlet of the ultraviolet disinfection device is connected to the natural water body discharge pipe. A transition buffer layer is provided between the volcanic rock packing layer and the ceramsite packing layer of the combined packing layer. The transition buffer layer is composed of zeolite particles with a particle size of 8-10 mm and a calcium ion exchange capacity of ≥200 mg / g, with a thickness of 50-80 mm. The polyurethane biocarrier layer has a through-hole microporous channel with a diameter of 1-1.5 mm. The inner wall of the microporous channel is coated with a nano-titanium dioxide photocatalytic coating with a thickness of 10-20 μm. The thickness of the polyurethane biocarrier layer is 0.4-0.6 μm, and the porosity of its microporous channel is ≥85%, and the wet compression resilience is ≥90%. The aeration pipes of the aeration system form a swirling aeration structure at the bottom of the combined packing layer, and the aeration holes of the aeration system are inclined at an angle of 30-45 degrees. The humus planting layer is composed of the following components mixed in the following mass ratio: The soil contains 60%-70% humus, with an organic matter content ≥25% and a pH of 6.0-7.

5. 15%-20% modified biochar particles, particle size 2-4mm, specific surface area ≥500m² 2 / g, with a surface loading of 3%-5% Fe-Mn oxides by mass; 10%-15% diatomite-zeolite composite particles, particle size 1-3mm, calcium ion exchange capacity ≥180mg / g; 5%-8% slow-release microbial inoculant granules, including nitrifying bacteria, denitrifying bacteria, and plant rhizosphere growth-promoting bacteria, with a content ≥1×10 6 CFU / g, ≥5×10 5 CFU / g, ≥2×10 6 CFU / g; The humus planting layer is divided into a top layer and a bottom layer from top to bottom. The top layer is 50-80mm thick and includes a mixture of humus and modified biochar in a 7:3 mass ratio. Reeds, calamus and irises are planted in the top layer, with the three plants arranged at a 2:1:1 ratio. Spiral drainage channels are provided in the root zone. The spiral drainage channels are 20-30mm deep and the channel spacing is 80-100mm. The bottom layer is 150-220mm thick and consists of a mixture of humus and diatomaceous earth-zeolite composite particles in a 6:4 mass ratio. The bottom layer is pre-embedded with permeable ceramic granule pipes with a diameter of 10-15mm. The horizontal spacing of the permeable ceramic granule pipes is 200-250mm and the vertical spacing is 100-150mm.

2. The biological-ecological synergistic purification system according to claim 1, characterized in that, The perforated water collection pipe is surrounded by a volcanic rock particle filter layer with a particle size of 3-5mm, the thickness of the volcanic rock particle filter layer is 80-100mm, and the porosity of the volcanic rock particles is 45%-55%. The perforated water collection pipe is divided into upper and lower layers. The upper layer perforated water collection pipe has an opening direction of 15%-18% and an opening rate of 15%-18%. The lower layer perforated water collection pipe has an opening direction of 12%-15% and an opening rate of 12%-15%. The distance between the upper and lower layers of perforated water collection pipes is 200-250mm.

3. The biological-ecological synergistic purification system according to claim 2, characterized in that, It also includes a backwashing system, which includes a municipal water supply pipe and an ultraviolet disinfection return water pipe connected by a three-way valve. The backwash water is injected into the perforated water collection pipe in reverse through the backwashing branch pipe. The end of the backwashing branch pipe is connected to the sludge collection tank. The bottom of the sludge collection tank is connected to the sludge treatment equipment through a screw conveyor. The perforated water collection pipe is connected to a backwash branch pipe at its end. A pressure sensor is installed on the backwash branch pipe. When the pressure difference between the inside and outside of the water collection pipe exceeds the set threshold, the backwash mode is triggered.

4. The biological-ecological synergistic purification system according to claim 1, characterized in that, The inlet of the ultraviolet disinfection device is equipped with a turbidity sensor and a flow meter. When the turbidity is greater than 5 NTU or the flow rate exceeds the design value by 20%, the PLC controller will synchronously control the lamp power of the ultraviolet disinfection device to increase to 100%-110% and operate at overpower for no more than 30 minutes at a time. An ultraviolet intensity monitoring probe is installed at the end of the ultraviolet disinfection device. When the detected dose is <30mJ / cm², the water flow residence time is extended to 1.2-1.5 times the original value.

5. The biological-ecological synergistic purification system according to claim 1, characterized in that, An ultrasonic level sensor is installed on the side wall of the sedimentation tank. The height of the probe of the ultrasonic level sensor from the bottom of the sedimentation tank is 2 / 3 to 3 / 4 of the depth of the sedimentation tank, and the detection is performed at the set detection frequency. The sludge discharge pipe inlet is equipped with a pneumatic knife gate valve with a gate thickness of 8-10mm; The ultrasonic level sensor is connected to the PLC controller. When the sludge layer height is detected to be greater than 1 / 2 of the sedimentation tank depth for three consecutive times, the PLC controller controls the pneumatic knife gate valve to fully open within 15 seconds to discharge sludge until the ultrasonic level sensor detects that the sludge layer height is less than the set low threshold. At this point, the pneumatic knife gate valve closes, the sludge discharge pipe outlet is connected to the screw conveyor inlet, and the screw conveyor outlet is connected to the sludge treatment equipment receiving bin.

6. The biological-ecological synergistic purification system according to claim 2, characterized in that, Three dissolved oxygen sensors are installed at intervals along the water flow direction in the biofilm reaction tank, located 200 mm above the bottom of the combined packing layer, 150 mm below the middle and top of the combined packing layer, respectively. The blower of the aeration system is equipped with a frequency converter with an output frequency of 30-50Hz. The frequency converter is connected to the PLC controller via a 4-20mA signal. The PLC controller has a built-in segmented control algorithm. When the dissolved oxygen sensor values ​​of any two sensors are <2.5mg / L, the blower frequency is increased to 40-45Hz. When the dissolved oxygen sensor values ​​of all three sensors are >3.0mg / L, the frequency is reduced to 35-38Hz. The blower's outlet pipe is equipped with a bypass pressure relief branch pipe with a solenoid valve. This is for applications where the aeration intensity is greater than 1.2m. 3 / (m 2 ·h) After 5 minutes, the solenoid valve opens to 10%-15% of its maximum opening.

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